http://www.up.com/aboutup/community/community_ties/kinney-countyThis is a car-cleaning operation in south Texas. Hard to believe, but it cleans and washes box cars to make them food grade ready. Empties are then sent to Mexico for beer loading and return here to take care of us thirsty gringos.
So you have a destination for your box cars now, especially the 60 footers. Not an involved structure build. Then when the cars are "clean," they can move to staging to simulate interchange.
Also, google Atlantic Track and Turnout, Memphis. Satellite view will show nice detail for rail and switch restoration facility. Area to ship gons in and out and stage track components.